Effects Of Surface Modification Of Boron-doped Diamond On Electrochemical Sensing Performance

Boron-doped diamond（BDD）is commonly considered an ideal biosensing material because of exceptional advantages,such as a wide electrochemical window,high electrochemical stability and corrosion resistance,and high biocompatibility.However,traditional BDD electrodes have problems such as low sensitivity and large electron transfer resistance.In this paper,the pulse electrodeposition method was used to modify Pt and Ni metals on the surface of centimeter-level BDD plate electrodes to improve the active response of BDD electrodes to glucose.To further improve the electrochemical performance of BDD electrode,the surface modification of small size（micron level）BDD particle electrode was carried out,the surface modification of the micron-level BDD particle electrode was carried out,and the effects of Ni thermocatalytic etching and Au modification on their electrochemical properties were systematically studied.The main contents and conclusions are as follows:（1）By modifying Pt and Ni nanoparticles on the surface of traditional BDD plate electrodes,the effects of the monometallic and bimetallic nanoparticles on electrode electrochemical performance were compared.For the bimetallic nanoparticles,the effects of subsequent deposition and one-step co-deposition method on electrochemical properties were systematically studied.The results demonstrated that the bimetallic nanoparticles exhibited superior sensing performance than that of the monometallic nanoparticles and the sensitivity value is increased by 5times.Compared to the subsequent deposition method,the co-deposition method exhibited superior sensing performance and the sensitivity value is increased by 5 times with a detection sensitivity of 110.38μA·m M^-1·cm^-2.（2）The cBDD particles have the problems of low B-doping concentration and uneven distribution of B atoms,and show selective etching and selective deposition on the crystal surface.Combined with the experiment of（1）,the preparation of homogeneous highly B-doped BDD particles microelectrodes was achieved by depositing highly B-doped polycrystalline BDD films on the cBDD surface.After the modification,the electrochemical performance of the particle electrode was improved.And the electrochemical activity area was increased from 0.44 mm² to 0.90mm²,and the electron transfer rate constant increased from 0.24×10^-3 cm·s^-1 to 0.48×10^-3 cm·s^-1.After further Ni thermocatalytic etching and Au nanoparticle deposition,the electron transfer rate constant increased by12.7 times,and the electrochemical activity area increased by 3.3 times.In addition,by etching porous and modifying Au nanoparticles on the surface of cBDD particles,the linear current response to ascorbic acid and dopamine was achieved,and the sensitivity reached 19.67μA·m M^-1·cm^-2and 81.36μA·m M^-1·cm^-2,respectively.In addition,the sensitivity of Au-modified etched BDD particle for dopamine and ascorbic acid was 81.36μA·m M^-1·cm^-2 and 19.67μA·m M^-1·cm^-2,respectively.